JPH08192422A - Plastic pellet manufacture apparatus - Google Patents

Abstract

PURPOSE: To prevent the lateral slip of a strand by supporting the base part of a housing having a small diameter press roll having a specific diameter provided at the leading end thereof so that the press roller is set at the position close to a cutter on a fixed blade so as to be freely revolvable in its circumferential direction. CONSTITUTION: When the leading end of a strand S is held between tension rollers 2 to be transferred forwardly, the lever 51 provided on a housing 5 in a protruding state is pressed upwardly on the side of an extrusion molding machine to revolve the housing 5 and the pin 3p formed on the side plate 3a of a roll unit is inserted in the groove 8a of the engaging jig 8 provided on the housing 5 to be passed through the ball 8c protruding from the groove 8a and pressed to the deep end of the groove 8a. By this constitution, the interval between a press roll 7 with a diameter of 10-30mm and a fixed blade stand 10 is kept wide to allow the leading end of the strand S to pass. Subsequently, when the pressing and holding of the lever 51 are released, the protruding part 5a of the housing 5 falls under its own wt. and the press roll 7 presses the strand S on the fixed blade stand 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention draws a molten plastic extruded from a die having a small-diameter hole (for example, a circle of 3 mm) mounted on the head of an extruder into a strand shape, cools it, and cuts it into pellets. The present invention relates to a cold-cut type pellet manufacturing apparatus. In this case, a filler such as a simple substance of plastic, glass, carbon fiber or metal powder, or foil may be filled.

[Prior art]

[0002] A method for producing pellets as a material used for injection molding of plastics is as follows. Plastics or plastics filled with various fillers are heated and kneaded by an extruder and extruded with a small diameter from a die attached to the nozzle. There is a hot cut method that directly cuts with a rotating cutter in contact with the face, and a cold cut method described below.

The cold cut method is disclosed in Japanese Patent Laid-Open No. 61-12.
No. 5813 and JP-A No. 62-5814. That is, the molten plastic extruded from the die 22 attached to the tip of the extruder 21 is guided as a strand by one or a plurality of pairs of tension rolls 2, while cold air is blown or passed through a water tank 23. Then, it is cooled and solidified by means of, and then cut to a predetermined length by a cylindrical cutter 12 which forms a fixed blade and several cutting blades on the outer periphery provided in contact therewith (FIG. 7).

[Problems to be Solved by the Invention]

As described above, after the molten plastic extruded from the tip die of the extruder is cooled and solidified, it is introduced by a pair of tension rolls or a plurality of pairs of tension rolls between a fixed pulling blade and a cutter having a rotary blade for cutting. However, due to the structure, the distance between the pair of rolls that sandwich and transfer the strand and the cutter is at least the radius of the roll (20 to 3).
The distance must be more than 0 mm). On the other hand, the cutter is formed by forming several cutting blades in a helical shape on the outer circumference of a column or a cylinder. Such a cutting blade cuts from one end of the circumference of a strand (diameter of about 3 mm) toward the other end in sequence, and the cutting pressure is applied to the strand in an inclined shape (helical angle). Become.
Therefore, the cutting performance of the blade deteriorates and the strands escape laterally on the fixed blade due to slippage with the cutting blade, normal pellets cannot be produced, and fine particles that are peeled off are generated, and the string-shaped cutting gradually occurs. Scrap will be generated.

As shown in phantom lines in FIG. 7, the one disclosed in JP-A-61-225813 has a flat guide 24 on the upper surface of the fixed blade 11 immediately before the cutter plus the strand wire diameter plus 0.05. ~ 0.2 mm gap (Publication p
5 are arranged in the right column from the third column). Since a gap is provided between the guide 24 and the strand, it is not possible to prevent the strand from escaping in the lateral direction due to the sliding of the cutting edge, so that the strip-like strip as described above is generated. The tip of the strand S first extruded from the die of the extruder is fixed to the fixed blade 11
It was not easy to introduce it between the guide and the guide 24, and it was a troublesome work.

[0006]

In order to eliminate the above-mentioned drawbacks, one to three small-diameter rolls are mounted immediately before the cutter, and the strands are pressed and sandwiched between the rolls and the fixed-side tool post surface. , The method of eliminating the lateral slip on the fixed blade is adopted. Moreover, one end of the housing, on which the small-diameter roll is mounted, is rotatably mounted on an appropriate position such as a support shaft of the tension roll or a roll unit side plate. It is also possible to engrave an uneven pattern on the surface of the small-diameter roll to prevent slippage, and to connect and rotate the motor through a transmission device such as a pulley or a belt.

Further, the circumferential surface (or roll unit) of the housing on which the roll for pressing and sandwiching the strand is mounted
A cylinder with a locking pin (or ball) that appears and disappears is attached to a U-shaped locking tool attached so that the tip of the locking pin projects into the groove inner surface. 2) is engaged with a pin protrudingly provided in (1) to maintain a state in which the distance between the strand pressing roll and the fixed blade is enlarged.

[0008]

According to the present invention, since the housing device which rotatably supports the small diameter roll is rotatably supported at one end thereof, if the roll side is lifted, the interval between the small diameter roll and the fixed blade becomes large. It will be released. Therefore, the tip of the strand S extruded from the extruder can be easily placed between the roll and the cutter stand and guided to the cutter section. Then
When the housing is lowered onto the fixed blade, the small-diameter roll rotates while pressing and sandwiching the advancing strand by the tension roll. The thus-pressed strand is cut without lateral slipping against a slightly oblique cutting pressure of the cutter, and a pellet having a normal shape can be obtained.

[0009]

Embodiments of the present invention will be described with reference to the drawings. 1 to 6 show the essential parts of a beretizer 1 according to the present invention. Generally, a pelletizer is used in combination with an extruder and a cooling device, and the outline thereof is shown in FIG.
Immediately before (on the right side of the figure), improvements were made on the fixed blade.

In FIG. 1, in a pair of tension rolls 2 for pulling a strand S extruded from an extruder (not shown), upper rolls 2t thereof are pivotally supported 2a, 2a on both side plates 3a, 3a of a roll unit 3, A pair of housings 5 and 5 in which protrusions 5a and 5a are formed in a part of the disk-shaped portion are rotatably fitted on both sides of the roll 2t coaxially via ball bearings 4 and 4. A scraping plate 6 is sandwiched between the pair of protrusions 5a, 5a such that one side below the scraping plate 5 is close to the roll 2t, and a small diameter (rhombus-like concave and convex pattern is engraved on the surface below the scraping plate 6). One (FIG. 1 etc.) to two (FIG. 6) three pressing rolls 7 having a diameter of about 10 to 30 mm are rotatably supported. Further, a ball cylinder 8b having a U-shaped cross section and a ball 8c pressed by a helical spring and slightly protruding into a groove 8a in a part of the disk-shaped portions of the housings 5 and 5 (above the protrusion 5a). A locking tool 8 having is attached. In addition, the engagement pin 3p that fits in the groove 8a in a loose fit is on the roll unit side plate 3a concentric with the groove 8a.
It is inserted in a protruding shape on the side surface. Reference numeral 5l is a lever projecting from the housing and is used for rotating the housing 5,5. The roll surface of the pressing roll 7 may be smooth without any uneven pattern, and it is more effective to coat the rubber plastic to prevent the strands from slipping.

As shown in FIG. 4, the ball cylinder 8b may be one in which a pin 8e having a tapered surface 8d at its tip is inserted into the cylinder and pressed downward by a coil spring 8s. According to this, as the housing 5 rotates, the above-mentioned engagement pin 3p slides on the tapered surface 8d at the tip of the pin 8e, pushes the pin 8e into the cylinder, and enters the depth of the groove, and the pin 8e is projected by the spring 8s. The engagement pin 3p is completely held. In this state, the tip of the strand is introduced onto the fixed blade, and then the upper end of the pin 8e is lifted to engage the engaging pin 3
will disengage from p.

One of the tension rolls 2 (2t, 2d) and the lower roll 2d are rotatably supported by a machine body (not shown) of the main body of the pelletizer 1 and rotated by a motor via a belt. A fixed-side tool rest 10 is installed in front of the roll 2d (left in FIG. 1) with its upper end 10a being close to the roll 2d, and a knife-fixing step is formed at the other end. A fixed blade 11 having a cutting blade 11a is detachably attached by a screw 11b.

The housings 5 and 5 are provided with protrusions 5a and 5a.
When a is at the lowest point, the lower surface of the outer circumference of the press roll 7 is in contact with the fixed-side tool rest 10 or at a position with a gap of 1 to 2 mm, and the outer circumference of the most advanced roll 7 is a cutter. It is located close to. A cutter 12 in which several helical cutting edges are formed on the outer peripheral surface of a cylinder or a cylinder,
A helical cutting blade is rotatably supported at a height almost equal to the blade surface of the fixed blade 11 in a state of being close to contact, and is connected to a motor 13 (see FIG. 7) via a belt or a gear.

A method of using the pelletizer 1 of the present invention having the above structure will be described. The tip end of the strand S of the molten plastic extruded from the extruder is introduced into the water tank to be cooled, and then sandwiched between the tension rolls 2 and transported forward. At this time, the lever 5l protruding from the housing 5
Is pushed upward from the extruder side and the housing is rotated to insert the pin 3p formed on the roll unit side plate 3a into the groove 8a of the locking tool 8 mounted on the housing 5 and project into the groove. The locking pin or the ball 8c to be passed is pressed against the inner end of the groove 8a (FIG. 2). In this way, the distance between the pressing roll 7 and the fixed tool rest 10 is kept wide. The tip of the strand S is passed within this interval. Then, when the locking pin is lifted or the pressing and holding of the lever 5l is released, the protruding portions 5a, 5a of the housing 5 are lowered by its own weight, and the pressing roll 7 presses the strand S on the tool rest 10 (Fig. 1). The tension roll 2 prevents the strand from sliding sideways due to the cutting pressure of the cutter while rotating with the advancing strand. Thus, the strands are correctly cut to a predetermined length and pellets P are produced. The pressing roll 7 may be connected to a motor via a pulley and a belt to rotate the roll 7.

The positional relationship between the engaging member 8 and the engaging pin 3p may be reversed, that is, the U-shaped engaging member 8 may be attached to the roll unit side plate 3a and the engaging pin 3p may be attached to the housing 5. . In this case, push up the lever 5l to move the housing 5
Is rotated and the engaging pin 3p is locked to the ball cylinder 8b to hold the protrusions 5a and 5a in the raised position (FIG. 6). In this way, the strand is introduced between the pressing roll 7 and the fixed-side tool post, and then the locking pin 3p
The structure may be such that the engagement between the ball cylinder 8b and the ball cylinder 8b is released, and the pressing roll 7 is lowered onto the strand. Further, as shown in FIG. 5, a stopper pin 3p is inserted into the housing 5 instead of the locking tool 8, and the housing 5 is lifted until it comes into contact with the engagement pin 3p to widen the distance between the pressing roll 7 and the fixed tool rest. It may be structured.

The right ends of the roll unit side plates 3a, 3a in the drawing are rotatably supported by the pelletizer body 3b (FIG. 5). The roll unit 3 is lifted with the shaft as a fulcrum. In this state, the maintenance between the tension rolls 2 or the cutter portion is performed in FIG.

[0017]

The pelletizer of the present invention having the above structure can easily introduce the strand tip extruded from the extruder between the pressing roll provided immediately before the cutter and the tool rest, and moreover, the pressing roll. Since the strand is pressing, the side slip of the strand is prevented even against the cutting pressure of a cutter having a helical cutting blade,
Therefore, the shape of the pellets to be cut is constant, and defective cutting and generation of chips due to the sliding of the strands are eliminated.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a usage state of a pelletizer equipped with a strand pressing roll according to the present invention.

FIG. 2 is a partial cross-sectional side view showing a state in which the housing is rotated to increase the gap between the press roll and the tool rest in order to introduce the tip of the strand into the lower part of the press roll.

FIG. 3 is a perspective view of a roller unit portion.

FIG. 4 is a side cross-sectional view showing an example of a locking tool that supports a press roll portion.

FIG. 5 is a partial cross-sectional side view showing a state in which a tension roll and a press roll are opened.

FIG. 6 is a side view of a partial cross section showing another example of a housing rotating and holding mechanism for enlarging the gap between the pressing roll and the tool rest.

FIG. 7 is a vertical cross-sectional view showing a conventional system of a pelletizer, an extruder, and a structure of a water cooling layer.

[Explanation of symbols]

 1 Belletizer 2 Tension roll 3 Roll unit 5 Housing 6 Scraping plate 7 Pressing roll 8 Locking tool 10 Fixed side tool post 11 Fixed knife 12 Cutter S Strand

Claims (3)

[Claims] 1. A pelletizing machine in which a strand of molten resin extruded from an extruder is cooled and then cut by a cutter having a fixed blade and several cutting blades on its circumferential surface, and a small pressing roll having a diameter of 10 to 30 mm. A plastic pellet manufacturing apparatus characterized in that the base of a housing having one to three tips is rotatably pivoted in a circumferential direction at a position where the pressing roll is close to the cutter on the fixed blade. . 2. An in-cylinder engaging pin that appears in and out of a groove of a U-shaped locking device mounted on the circumferential surface (or roll unit) of the housing engages with a pin protruding from the roll unit (or housing). The plastic pellet manufacturing apparatus according to claim 1, wherein the expanded state of the interval between the strand pressing roll and the fixed blade is maintained. 3. The plastic according to claim 1, wherein the small-diameter pressing roll made of steel has a smooth circumferential surface, or is engraved with a non-slip concave-convex pattern, or a rubber-based plastic is coated on the outer periphery of the roll. Pellet manufacturing equipment.