JPH09193234A - Parison pinch of hollow molding machine, method for cutting the parison and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parison pinch for sealing the cut part simultaneously upon cutting parison in a hollow molding machine, method for cutting the parison and apparatus therefor. SOLUTION: The parison extruded from a head is swung by rotating the shafts 6, 8 formed with racks 9 for sandwiching a pinion 10 between the holders 3 and 3a mounted with a pair of parison pinch bars 5 and cutters 4 and the ball screw 15 engaged with the nut 14 of the holder 3a by a motor 19. Thus, the parison is simultaneously pinched and cut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parison pinch and cutting method for a blow molding machine and an apparatus therefor, and more particularly,
The parison extruded from the head toward the mold held by the mold clamping device below the head is cut and sealed at the same time.

[0002]

2. Description of the Related Art As a parison cutting device for a hollow molding machine, there is a hot cutter disclosed in Japanese Unexamined Patent Publication No. 5-69474, in which an electric heater is stretched on a U-shaped holder and directed toward the parison. By moving the parison horizontally, the parison is fused by heat.

As a means for moving the holder back and forth toward the parison, an electric motor is used in the above publication, but an air cylinder is generally used.

[0004]

In the above-mentioned conventional example, since the parison in the state where the resin is molten is heated and cut, there is a risk of fire and lack of safety.
Since the burnt charcoal of the parison adheres to the electric heater, resulting in poor quality, there is an inconvenience that the cleaning must be performed frequently.

In general, when the parison is cut,
In order to perform good molding, it is preferable to pre-expand the parison by pre-blowing with the cut portion sealed and to insert the parison into the mold in the mold clamping device. However, in the method of fusing with a hot cutter, the cut portions are not sealed, so that the cut portions of the parison are not joined together. Therefore, a pinch (clamping) device other than the hot cutter was separately required to join the cut portions. It is not preferable to use a pinch device in addition to the cutting device, because it causes a problem of installation space and complicates the mechanism.

Further, when the air cylinder is used as a drive source for the forward and backward movement of the holder, the accuracy of the cutter operation is lowered due to the variation in the air pressure flow rate.

Therefore, the present invention provides a parison pinch for cutting the parison and a method for cutting the parison in the blow molding machine, and a device therefor.

[0008]

According to a first aspect of the present invention, there is provided a parison pinch and a cutting method for a hollow molding machine, wherein a parison extruded from a head is opened and closed by a program-controlled driving source. The parison pinch bar and the holder with the cutter are used to pinch and cut at the same time. Thereby, the parison pinch and the cutting can be performed at the same time.

According to a second aspect of the present invention, in the parison pinch and cutting device of the hollow molding machine, the parison extruded from the head is opened and closed by a holder to which a pair of parison pinch bars and a cutter are attached. It is characterized in that it is configured to pinch and cut at the same time in operation.

According to a third aspect of the present invention, the holder can slide on a plurality of shafts inserted into the fixing portion, and the pair of holders can be opened and closed through a rack and a pinion mechanism. According to claim 4, the pair of holders is opened and closed by a motor through a ball screw, and according to claim 5,
The motor is a variable speed type, and is configured to be program-controlled via a control unit. Further, according to claim 6, the pair of holders is opened and closed via an air cylinder. And

As a result, the parison with the cut lower end sealed is inserted into the mold held by the mold clamping device, and the moldability is improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a cutter 4 and a pinch bar 5 each made of a plate-shaped metal are horizontally placed on a pair of holders 3 and 3a facing each other with a parison 2 discharged from a head 1 of an extrusion device in a hollow molding machine interposed therebetween. The holders 3 and 3a are configured to be able to move back and forth toward the parison 2. The pinch bar 5 is formed to have a shorter protruding length than the cutter 4. Further, the cutters 4 and 4 are attached with a step in the vertical direction so that the blade edges contact each other like scissors.

That is, the shaft 6 having a predetermined stroke is connected to both ends of the holder 3, and the shafts 6 and 6 are connected.
The holder 3a is slidably engaged with the shaft 6,
6 is slidably engaged with a base 7 which is a fixed portion. Further, a shaft 8 having a predetermined stroke is connected near both ends of the holder 3a, and these shafts 8 and 8 are slidably engaged with the base 7.

The shafts 6 and 8 are juxtaposed at a predetermined interval, and racks 9 are formed on opposite side surfaces thereof, respectively, and a pinion 10 meshing with the racks 9 and 9 is rotatable. The shaft of the pinion 10 is supported by an upper plate 11 and a lower plate 12 which are horizontally mounted on the base 7.

A fastener 14, such as a power lock, which is attached to both ends of the bracket 13, is passed through the shafts 8 and 8. The fastener 14 can bite the shaft 8 to integrally connect the bracket 13 and the shaft 8. Then, a through hole is formed in a substantially central portion of the bracket 13, and the nut 15 is fixed coaxially with the through hole. A ball screw 16 screwed on the nut 15 is mounted on the base 7 to support the bearing 1.
The ball screw 1 is rotatably supported via 7, 17a.
The end of 6 is connected to a motor 19 via a coupling 18. The motor 19 is a variable speed type that can be controlled by a program like a servo motor.

Therefore, when the motor 19 operates, the ball screw 16 rotates and the bracket 13 can reciprocate within the base 7. Then, the movement stroke of the cutters 4, 4 is adjusted by the fastener 14 so that the movement of the bracket 13 does not come into contact with the pinion 10. Then, in the program control of the motor 19, the origin positions of the cutters 4 and 4 are set to a predetermined position (FIG. 1) apart from the parison 2.

The operation of the above embodiment will now be described. When the parison 1 is cut, the motor 19 is driven to rotate in the forward direction so that the ball screw 16 rotates in the forward direction and the bracket 13 is moved to the parison 2 side via the nut 15. Moving. The movement of the bracket 13 causes the shafts 8 and 8 to integrally move to the parison side via the fasteners 14 and 14, so that the pinions 10 and 10 rotate and the shafts 6 and 6 move to the motor 19 side. Therefore, as shown in FIG. 3, the cutters 4 and 4 move toward each other toward the parison 2 to close, and the parison 2 is cut by the blade edges contacting each other like scissors. At the same time, the pinch bars 5 and 5 come close to each other above the cutting portion and the parison 2
Pinch and seal.

Thereafter, the motor 19 is rotated in the reverse direction via the control unit, whereby the ball screw 16 is rotated in the reverse direction, and the bracket 13 is moved to the motor 19 side via the nut 15. The movement of the bracket 13 causes the shafts 8 and 8 to move integrally to the motor 19 side through the fasteners 14 and 14, so that the pinions 10 and 10 rotate in reverse and the shafts 6 and 6 rotate.
6 moves to the parison 2 side. Therefore, as shown in FIGS. 1 and 2, the cutters 4 and 4 move toward each other toward the parison 2 and open.

Note that another embodiment of the present invention will be described with reference to FIGS. In FIGS. 4 and 5, the same reference numerals as those in FIGS. 1 and 2 denote the same components, and a duplicate description will be omitted. The difference from this form in this form is
Take the bracket 13 out of the base 7, and remove the shaft 6,
6 is slidably engaged with the fasteners 14, 14 and the piston rod 20 is connected to a substantially central portion of the bracket 13. The piston rod 20 penetrates the front end of the base 7 via a slide bearing 17b and engages with the air cylinder 21. The air cylinder 21 is programmable. The air pressure supply device of the air cylinder 21 and its program control method are well known or well known, and therefore detailed description thereof will be omitted.

[0020]

According to the present invention described above, since the cut portion is pinched and joined at the same time when the parison is cut and the parison is sealed, it is uneconomical to separately cut and seal, and the installation space is reduced. I was able to solve problems in a compact way.

Since the cut portion is sealed at the same time as the parison is cut, the amount of air in the pre-blow is stabilized, and the parison diameter and length before the mold clamping are made constant to improve the moldability. The quality of the product is improved.

Further, since the parison pinch and cutting are carried out by a holder equipped with a pair of parison pinch bars and cutters which are opened and closed via a ball screw by a program-controlled motor, the position of the seal is determined depending on the thickness of the parison. There is no need for adjustment and the convenience that the holder stop position and speed can be changed arbitrarily.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an explanatory diagram of an operation.

FIG. 4 is a partial sectional side view showing another embodiment of the present invention.

FIG. 5 is a plan view of FIG. 4;

[Explanation of symbols]

 1 ... Head 2 ... Parison 3, 3a ... Holder 4 ... Cutter 5 ... Pinch bar 6, 8 ... Shaft 7 ... Base (fixed part) 9 ... Rack 10 ... Pinion 13 ... Bracket 14 ... Fastener 15 ... Nut 16 ... Ball screw 19 … Motor 20… Piston rod 21… Air cylinder

Claims (6)

[Claims] 1. A hollow molding machine characterized in that a parison extruded from a head is pinched and cut at the same time by a holder equipped with a pair of parison pinch bars and a cutter that is opened and closed by a drive source controlled by a program. Parison pinch and cutting method. 2. A parison pinch and cutting device configured to simultaneously pinch and cut a parison extruded from a head by opening and closing a holder to which a pair of parison pinch bars and a cutter are attached. . 3. The parison according to claim 4, wherein the holder is slidable on a plurality of shafts penetrating the fixing portion, and the pair of holders are opened and closed via a rack and a pinion mechanism. Pinch and cutting device. 4. The parison pinch and cutting device for a hollow molding machine according to claim 4, wherein the pair of holders are opened and closed by a motor through a ball screw. 5. The parison pinch and cutting device according to claim 6, wherein the motor is of a variable speed type and is configured to be program-controlled via a controller. 6. The parison pinch and cutting device for a hollow molding machine according to claim 2, wherein the pair of holders are opened and closed via an air cylinder that is program-controlled by a controller.