JP4292845B2 - Blow air exhaust apparatus and exhaust method in blow molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a molding machine for molding a molded product such as a hollow container, and in particular, a blow air exhaust device in a blow molding machine for molding a molded product of a predetermined shape by blowing air into a material in the mold after the mold is closed. And an exhaust method.
[0002]
[Prior art]
As a blow molding machine that blows air into the material in a mold to form a molded product of a predetermined shape, a plurality of molds are arranged in an annular shape on a base, and this mold is rotated while rotating together with the base. There is known a rotary blow molding machine for molding a molded product. Such a rotary blow molding machine is used for molding a molded product such as a hollow container. The parison (material) extruded from the die head is received by a pair of split molds, and the mold is closed. The air is blown in, and then the mold is opened to take out the molded product (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 52-58671 (see detailed description of the invention in the specification)
[Patent Document 2]
JP 2000-296826 A (see column [0020] in the specification)
[Patent Document 3]
Japanese Unexamined Patent Publication No. 2000-313056 (refer to the detailed description of the invention in the specification)
[0004]
In such a rotary blow molding machine, a plurality of split molds are fixed to an annular rail, and each split mold is continuously opened and closed while moving in a ring, and the molded product is rotated while the annular rail is rotated once. The blow molding is completed by performing the process up to take-out. A rotary blow molding machine can mold a molded product with a large number of annular molds, for example, 8 to 14 split molds, so that it can be efficiently molded when mass-producing the same type of molded product. There is an advantage that can be.
[0005]
13 is a front view of the main part of a rotary blow molding machine for forming a hollow container, FIG. 14 (a) is an enlarged partial cross-sectional view of a main part of a mold of the blow molding machine, and FIG. (b) And (c) is a figure which shows the II-II direction cross section in (a) of the exhaust hole formed in the metal mold | die.
The rotary blow molding machine includes a molding unit 6 in which a plurality of (eight in this embodiment) molds 220 are arranged at equal intervals on the same circumference, and a predetermined position (station ▲) of the molding unit 6. 1) and a die head 5 for supplying a parison (material), and a molded product take-out portion 8 for taking out the molded product from the mold 220 at the next predetermined position (station (7)).
The molding unit 6 is configured by attaching the mold 220 to the annular base 61 at equal intervals, and the mold 220 and the base 61 are driven by the rotation driving unit 65 provided at the center of the base 61 as shown in FIG. Rotates in the clockwise direction.
[0006]
In the rotary blow molding machine, the upper die and the lower die constituting the mold 220 are supplied while the parison is supplied from the die head 5 at the station (1) and moved from the stations (1) to (2). At station (3), the blow nozzle 222 is inserted into the mold 220 from the radial direction of the rotation circumference of the base 61, and air is blown into the parison at station (3). It is. The nozzle 222 is preferably inserted into a flash portion or a flash portion that is removed from the molded product after being taken out from the mold 220. By blowing air from the nozzle 222, the parison swells into a shape corresponding to the cavity 221, cooled while moving from station (3) to (6), and taken out by the molded product take-out section 8 at station (7). .
[0007]
By the way, in the conventional rotary blow molding machine described above, as shown in FIG. 14A, an exhaust hole 223 communicating with the cavity 221 is formed in the mold 220, and the internal pressure of the molded product is constant by the blown air. When this is the case, the molded product is partially ruptured at the exhaust hole 223 to form an opening. Then, air in the molded product is released into the atmosphere from the opening through the exhaust hole 223, and air is circulated inside the molded product to cool the molded product.
[0008]
The timing at which a part of the molded product is partially ruptured to form an opening and air is exhausted and circulated varies depending on the shape, thickness, size, and the like of the molded product. For example, in a molded product having a complicated shape, it is necessary to delay the timing of opening formation as much as possible in order to increase the pressing time of the molded product against the cavity 221 by air pressure. Conventionally, such timing adjustment has been performed by adjusting the hole diameter of the exhaust hole 223. That is, as shown in FIGS. 14 (b) and 14 (c), in order to delay the timing at which the opening is formed, the hole diameter of the exhaust hole 223 is reduced (the smaller hole diameter is denoted by d1 in FIG. 4 (b)). In order to speed up the timing, the hole diameter d2 of the exhaust hole 223 is increased (a large hole diameter is indicated by a symbol d2 in FIG. 4C).
[0009]
However, there is a problem that it is extremely difficult to adjust an appropriate timing depending on the hole diameter of the exhaust hole 223. Of course, when the shape, size, thickness, and the like are different, even when the molded product has the same shape, when the thickness is different, the timing for forming the opening may need to be changed. For this reason, it is necessary to prepare and store a plurality of types of molds 220 in which exhaust holes 223 having different hole diameters are formed, and there is a problem that the cost becomes high, and it takes time to replace the molds 220 and molding. There is a problem that the productivity of goods is reduced.
[0010]
Further, if the hole diameter of the exhaust hole 223 is reduced in order to delay the opening formation timing, the exhaust amount is restricted, and it takes time until the air inside the molded product is completely exhausted. There is a problem that the rotational speed of the mold 220 cannot be increased sufficiently. For this reason, when molding a molded product having a complicated shape, etc., it is desired to improve the rotational speed of the mold 220 by exhausting quickly after the opening is formed while sufficiently delaying the opening formation timing. There is a request.
In addition, when the molding conditions when molding a molded product with a rotary blow molding machine, such as the mold rotation speed, mold ambient temperature, and blow air temperature change, change the start timing of exhaust. There is also a demand to be able to mold a higher quality molded product by changing the molding conditions.
[0011]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems and requirements, can easily adjust the timing of opening formation, and can change and adjust the timing even during operation of the molding machine, It is an object of the present invention to provide a blow-air exhaust apparatus and exhaust method having a simple configuration capable of improving the quality and productivity of a molded product.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, after a material is supplied from a material supply unit to a mold and air is blown into the material in a closed state, a molded product having a predetermined shape is formed. A blow air exhaust device in a blow molding machine for forming an opening in a part of the molded product and exhausting air inside the molded product, the exhaust hole formed in the mold, and the exhaust hole And an opening / closing means for opening / closing the opening and a control means for controlling the timing of opening the exhaust hole by the opening / closing means. The opening / closing means is a switching valve that maintains the inside of the exhaust hole at a predetermined pressure and opens the exhaust hole when exhausting air inside the molded product. The configuration is as follows.
[0013]
According to this configuration, it is possible to easily adjust the timing of exhausting air from the molded product. Moreover, even if the shape, thickness, size, etc. of the molded product change, it is possible to cope with this by adjusting the timing of opening the exhaust hole without having to replace the mold with a different diameter of the exhaust hole.
[0014]
The exhaust device of the present invention is Claim 2 As described in the above, it can be applied to a rotary molding machine in which a plurality of molds are arranged in a ring shape on a base, and a molded product having a predetermined shape is formed while rotating the mold together with the base. .
[0015]
The purpose of the present invention is to Claims 3-7 This can also be achieved by the method described in any of the above.
[0016]
That is, Claim 3 The method described in Mold A blow air exhausting method in a blow molding machine for supplying a material to a material and blowing air to the material at a predetermined position to form a molded product of a predetermined shape, wherein an exhaust hole having a predetermined diameter is previously formed in the mold The exhaust hole is opened and closed at a predetermined timing, and the molded product is opened by the blow air pressure. At this time, the pressure in the exhaust hole is maintained at a predetermined pressure, and the air in the exhaust hole is opened to the atmosphere at the predetermined timing, so that the molded product is opened by the pressure of the blow air. I am doing so.
[0017]
In the present invention, Claim 4 As blow air, Within the range of -30 ° C to -40 ° C Low temperature air may be used.
Thus, the productivity of the molded product can be further improved by the combined use with the low temperature air blow.
In this case, the temperature of the low-temperature air is preferably about -35 ° C.
[0018]
In the present invention, Claim 5 A mold closing period in which the mold is closed, While the mold is rotated 225 ° Good.
By doing in this way, the rotational speed of a metal mold | die can be made quick and the productivity of a molded article can further be improved.
[0019]
Further, in the present invention, a sixth aspect is provided. As described in the above, the blow molding machine is a rotary type molding machine, and the material supply is preset based on the peripheral speed of the mold to start the material supply from the material supply unit. And a material discharge from the material supply unit is started. When In addition, Material tension means The material supply unit, the material discharged from the material supply unit is received by the material pulling means, and the material is fed at a speed equal to or faster than the peripheral speed of the mold. After the step of pulling in one direction and the discharge amount or discharge speed of the material reach a preset amount or speed, Material cutting means Cutting the material according to the above, cutting the material, and setting the material pulling means in advance timing And starting the supply of material from the material supply unit to the mold, and adjusting the timing of supplying the material to the mold.
[0020]
further, Claim 7 As described in the above, the blow molding machine is a rotary molding machine, and the supply of the material pre-sets the material supply stop timing based on the peripheral speed of the mold; Mold rotation stop means Is operated at the stop timing Material tension means A step of moving the material forward to the material supply unit side, and the mold rotation A step of rotating a predetermined number of molds after the stop means is operated and taking out a molded product in the mold, and adjusting the timing of stopping the supply of the material to the mold Good.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, referring to the drawings, After explaining the reference example, DESCRIPTION OF EMBODIMENTS Preferred embodiments of a blow air exhaust apparatus and exhaust method according to the present invention will be described.
FIG. First reference example of exhaust device and exhaust method (A) shows the state before the start of exhaust, and (b) shows the state at the start of exhaust.
An exhaust hole 225 communicating with the cavity 221 is formed in the mold 220 at a position facing the blow nozzle 222. Book Reference example Then, since the timing for forming the exhaust opening in a part of the molded product is performed by the exhaust device described below, the hole diameter of the exhaust hole 225 can be arbitrarily set. When the opening is formed in the molded product, it is preferable to select the hole diameter so that the air inside the molded product is quickly exhausted. By selecting such a hole diameter, the rotational speed of the mold 220 can be increased and the productivity of the molded product can be increased.
[0022]
A valve body 232 is provided on the same axis as the exhaust hole 225 so as to be movable back and forth in the same direction as the axis. The valve body 232 is preferably formed of a material having excellent heat resistance and sealing properties, such as heat resistant rubber or heat resistant resin. At a position facing the exhaust hole 225, a cylinder 231 such as an air cylinder having a piston rod 231a that can move forward and backward is provided. The valve body 232 is attached to the tip of the piston rod 231a, and moves forward and backward together with the piston rod 231a by driving the cylinder 231. Then, the valve body 232 moves to the exhaust hole 225 side and is pressed against the inlet, so that the exhaust hole 225 is closed. Accordingly, the opening is not easily formed by the pressure of the blow air supplied into the molded product. Further, even if a part of the molded product ruptures and an opening is formed due to the difference between the internal pressure of the exhaust hole 225 in the closed state and the internal pressure of the molded product, air circulation does not occur inside the molded product. Like that. Therefore, the volume in the exhaust hole 225 closed by the valve body 232 is preferably as small as possible, and the inlet portion is preferably provided at a position as close as possible to the cavity 221.
[0023]
The driving of the cylinder 231 is controlled by a control device that controls opening and closing of the mold 220 and supply and stop of blow air.
FIG. 2 is a chart showing the opening / closing timing of the mold 220, the timing of supplying and stopping blow air, and the timing of exhausting the air inside the molded product.
As shown in FIG. Reference example Then, two times of air blow of primary blow and secondary blow are performed on the molded product at different timings.
The primary blow is started immediately after the mold is completely closed, and the secondary blow is started immediately before the primary blow is finished. By the primary blow and the secondary blow, the parison in the cavity 221 expands and is pressed against the inner surface of the cavity 221. The internal pressure of the molded product by the primary blow and the secondary blow is maintained until just before the mold opening is started, and the pressed state against the inner surface of the cavity 221 of the parison is maintained.
Then, the valve body 232 is separated from the exhaust hole 225 by driving the cylinder 231 at the timing shown in FIG. As a result, the molded product is partially ruptured at the exhaust hole 225, and air inside the molded product is released into the atmosphere from the formed opening.
Note that the timing of starting exhaust, that is, the timing of driving the cylinder 231 is individually determined in advance according to the thickness, shape, size, etc. of the molded product.
[0024]
Next, the second reference example Will be described with reference to FIGS.
FIG. Second reference example of exhaust device and exhaust method FIG.
As shown in FIG. Reference example The exhaust hole formed in the mold 220 in FIG. Reference example Is an exhaust hole 226 formed at the same position. A contact member 234 that can be inserted into and removed from the exhaust hole 226 is provided on the axis of the exhaust hole 226 so as to be movable forward and backward. The contact member 234 is formed to have an outer diameter substantially the same as the inner diameter of the exhaust hole 226, and the first Reference example The same cylinder 231 moves forward and backward. When the abutting member 234 is inserted into the exhaust hole 226, the tip of the abutting member 234 abuts on the molded product so that an opening is not formed against the air pressure inside the molded product. .
this Reference example Also, the driving of the cylinder 231 is the first Reference example It is controlled by the control device described in 1. Then, the cylinder 231 is driven at the timing shown in FIG. 2, and the contact member 234 is separated from the exhaust hole 226, whereby the molded product is partially ruptured to form an opening.
[0025]
FIG. 4 shows an exhaust apparatus and exhaust method according to the present invention. Embodiment FIG.
As shown in FIG. 4, a pressurizing chamber 235 communicating with the exhaust hole 227 is formed in the mold 220 of this embodiment. The pressurizing chamber 235 is connected to a pressurizing means 239 such as a compressor via an exhaust pipe 235a, and pressurizes the pressurizing chamber 235 and the exhaust hole 227 communicating with the pressurizing chamber 235 with a predetermined pressure. Yes. The pressurizing pressure of the pressurizing chamber 235 and the exhaust hole 227 is smaller than the air pressure inside the molded product so as not to hinder the molding of the molded product, and the molded product until a predetermined timing comes. Select one that does not rupture or form an opening.
[0026]
The pressurization is started and stopped by a switching valve 236 provided between the exhaust pipe 235a and the pressurizing means 239. The control of the switching valve 236 is controlled by the first Reference example And second Reference example It is performed by the same control device. Further, the switching timing of the switching valve 236 is, as shown by a two-dot chain line in FIG. 2, the pressurization is started after the start of the secondary blow that is high-pressure air, and the exhaust timing determined for each molded product. It may be set to exhaust after the pressurization is finished.
In order not to disturb the molding of the molded product by blow air, it is preferable to gradually increase the pressurizing pressure according to the increase of the air pressure inside the molded product.
[0027]
After the blow air is supplied into the cavity 221 and the molded product is molded, the switching valve 236 is switched at a predetermined timing, and the pressurizing chamber 235 is opened to the atmosphere. The pressure difference between the pressurizing chamber 235 and the exhaust hole 227 suddenly increases, the molded product bursts and opens at the exhaust hole 227, and the air inside the molded product is released into the atmosphere.
[0028]
In the exhaust method of the present invention, the effect is increased by using low-temperature air as blowing air.
FIG. 5 is an enlarged view of a main part of a rotary molding machine for carrying out the blow molding method of the present invention. FIG. 5 (a) is a longitudinal sectional view of a blow air supply section in the rotary molding machine, and FIG. It is II sectional drawing of (a).
[0029]
A fluid passage hole 652 for supplying a cooling fluid (cooling water) to the mold 220 is formed through the rotation shaft 651 of the molding unit 6 on the axis of the central axis C. In addition, fluid (pressure oil) flow holes 653 for opening and closing the mold 220 are formed on concentric circles with the central axis C as the center, corresponding to each of the stations (1) to (8). Yes.
Air flow holes 664 for supplying blow air to the material in the mold 220 are formed away from the fluid flow holes 652 and 653, and are attached to the outer peripheral surface of the rotary shaft 651. The heat insulating member 661 made of resin or the like prevents the low temperature air flowing through the air circulation hole 664 from being heated by cooling water or pressurized oil, or the rotating shaft 65 from being adversely affected by the low temperature air.
[0030]
Eight air circulation holes 664 are formed at equal intervals in the peripheral wall of the cylindrical body 662 attached to the outer periphery of the heat insulating member 661 according to the number of molds 220. The cylindrical body 662 is connected to the rotating shaft 651 by a connecting member 669 and rotates integrally with the rotating shaft 651.
A coupler 663 is attached to one opening of the air circulation hole 664, and the blow nozzle 222 (see FIG. 14A) and the air circulation hole 664 are connected via the coupler 663.
[0031]
Further, a ring-shaped rotating member 666 that is rotatable with respect to the cylindrical body 662 is attached to a portion where the other opening of the air circulation hole 664 is formed. An air supply hole 667 communicating with the other opening of the air circulation hole 664 is formed at a position corresponding to a predetermined station (station {circle around (3)}) of the rotating member 666. When the mold 220 is positioned at the station (3), low temperature air is supplied from the air supply hole 667 to the air circulation hole 664.
The temperature of the low-temperature air supplied for blowing is between -30 ° C and -40 ° C, preferably about -35 ° C.
[0032]
The timing at which the low-temperature air is supplied from the air circulation hole 664 to the material in the mold 220 is the same as the conventional blow air supply timing.
In addition, an air pipe that supplies low-temperature air to the air circulation hole 664 and the air supply hole 667 and an air pipe that connects the air circulation hole 664 and the mold 220 are covered with a heat insulating material to keep the low-temperature air warm. preferable. Further, the bearing 665 provided at the contact portion between the rotating member 666 and the cylindrical body 662 is also preferably made of resin or ceramic having excellent heat insulation.
[0033]
FIG. 6 is a graph showing changes in the temperature of the bottom of the bottle (molded product) when low temperature air having a temperature of −35 ° C. is used as blow air.
When blow with low temperature air is not performed, that is, with high temperature (about 11 ° C.) air used in conventional blow molding, the temperature gradually increases after the bottle is taken out from the mold 220. However, this seems to be because heat in other parts of the bottle moves to the bottom when the bottle is removed from the mold 220.
[0034]
On the other hand, in the case of using the low temperature air, it can be seen that the cooling by the low temperature air is efficiently performed, and the temperature rise after the bottle is taken out from the mold 220 is hardly observed. This indicates that the rotation speed of the mold 220 can be increased by about 20% to 25% from the state where the mold closing period of the mold 220 is not extended and the low temperature air is not blown.
[0035]
In the present invention, it is possible to further increase the rotational speed of the mold 220 by extending the mold closing period of the mold 220.
Hereinafter, specific means for extending the mold closing period of the mold 220 will be described.
FIG. 7 is a front view of an essential part of an example of a rotary molding machine that can lengthen the mold closing period of the mold 220.
In the vicinity of the die head 5 as a material supply unit for supplying the parison to the mold 220, a timing adjusting device 7 for adjusting the supply timing of the parison supplied from the die head 5 to the mold 220 immediately after the start of the operation of the rotary molding machine. Is provided.
[0036]
The timing adjusting device 7 receives a base 71 fixed to a fixed portion of the rotary molding machine and a parison discharged from the discharge port 5a of the die head 5, and is faster than the discharge speed of the parison from the die head 5, preferably Is a conveyor 72 as material pulling means for pulling the parison in the lateral direction at the same speed as or faster than the peripheral speed of the rotating mold 220, and a parison cutting section for cutting the parison in the vicinity of the discharge port 5a. 73.
In this specification, “circumferential speed” refers to the speed in the tangential direction of the mold 220 on the rotational circumference R of the mold 220 passing through the center of the mold 220.
[0037]
The conveyor 72 supports a motor 721 that is movable in a forward direction approaching the die head 5 and a backward direction away from the die head 5 while being guided by a first guide rail 711 provided on the base 71. And a pulley support member 727 extending from the housing to the die head 5 side in parallel with the first guide rail 711 and a rear end (right end in FIG. 7) of the pulley support member 727 so as to be rotatable. A driving pulley 722 that is supported and rotated by driving of the motor 721, a driven pulley 723 that is rotatably supported by the front end (left end in the figure) of the pulley support member 727, the driving pulley 722, and the driven pulley 723 and a belt 724 wound around 723. Therefore, when the motor 721 is driven and the driving pulley 722 rotates, the belt 724 travels in the clockwise direction in the drawing along with the rotation of the driven pulley 723.
[0038]
In the vicinity of the front end of the pulley support member 727, an inverted L-shaped support member 725 is erected, and a rotatable roller 726 is attached to the tip thereof. The roller 726 is positioned so as to be positioned almost directly below the discharge port 5a of the die head 5 when the roller 726 moves forward together with the motor 721 and the pulley support member 727, and is attached to the pulley support member 727. When 72 pulls the parison, it serves as a guide roller that changes the direction of the parison discharged from the discharge port 5a.
[0039]
The parison cutting unit 73 cuts the parison discharged from the die head 5 at a preset timing. The parison cutting portion 73 includes a saddle 731 capable of moving forward or backward toward the die head 5 along a second guide rail 712 parallel to the first guide rail 711 of the base 71, and a saddle via a bracket 733. A rod 735 that moves forward and backward in the same direction as the saddle 731 while being guided by a cylinder 732 attached to the saddle 731, a guide 738 provided in the saddle 731, and a guide hole formed in the bracket 733, and a front end of the rod 735 And a cutter 735 provided on the surface. Since the saddle 731 is connected to the casing of the motor 721, the saddle 731 is integrated with the conveyor 72 and moves forward or backward in the same direction.
[0040]
The piston rod 732a of the cylinder 732 can move forward and backward in the same direction as the forward and backward movement of the rod 735, and the tip of the piston rod 732a and the rear end of the rod 735 are connected by a connecting member 734. Therefore, when the cylinder 732 is driven and the piston rod 732a moves forward and backward, the rod 735 and the cutter 736 move forward or backward toward the die head 5 as the piston rod 732a moves.
[0041]
Next, the material supply procedure in this rotary blow molding machine will be described together with the operation of the timing adjusting device 7 with reference to FIGS.
FIG. 8 is a flowchart for explaining the material supply procedure, and FIGS. 9 and 10 are schematic views for explaining the operation of the timing adjusting device 7.
[0042]
First, the timing for supplying the parison discharged from the discharge port 5 a of the die head 5 to the mold 220, that is, the timing for retracting the conveyor 72 and the timing for cutting the parison by the cutter 736 in advance with respect to the rotation timing of the mold 220. Adjust it. For example, the motor drive pulses of the rotation drive unit 65 (see FIG. 13) that rotates the mold 220 are counted, and the best timing for moving the conveyor 72 backward is adjusted, and the timing for driving the cylinder 732 is adjusted.
[0043]
Then, when the mold 220 enters the station (1), the conveyor 72 is moved backward at the timing when the tip of the parison is accurately supplied to the predetermined position of the mold 220, and the parison is cut. To do.
In addition, a necessary and sufficient amount of parison can be supplied to the mold 220 of the station (1) before the mold 220 shifts from the station (1) to the station (2). As described above, the discharge amount (discharge speed) of the parison of the die head 5 is set in advance.
[0044]
The parison discharge timing and discharge amount obtained by the above procedure are unchanged as long as the same mold 220 and the same material parison are used. Therefore, even if the mold 220 is changed or the material of the parison is changed, the blow molding machine can be operated immediately by simply setting the timing and the discharge amount determined in advance according to the mold 220 and the parison of the material. It is possible to start.
[0045]
As shown in FIG. 9A, in the initial state before the blow molding machine starts operation, the conveyor 72 of the timing adjustment device 7 and the cutter 736 of the parison cutting unit 73 are in a retracted state separated from the die head 5. It has become.
When molding of the molded product by the blow molding machine is started (step S10), the driving body 713 is driven to advance the conveyor 72 (step S11). Accordingly, as shown in FIG. 9B, the belt 724 and the roller 726 are positioned directly below the discharge port 5 a of the die head 5.
[0046]
Simultaneously with the advancement of the conveyor 72, the driving of the motor 721 is started and the belt 724 is caused to travel. As described above, it is preferable that the traveling speed of the belt 724 is the same as or slightly higher than the peripheral speed when the mold 220 rotates (step S12).
Thereafter, discharge of the parison P is started from the die head 5 (step S13). The parison P discharged from the die head 5 is pulled laterally by the belt 724 as shown in FIG. 9C (step S14). At this time, the roller 726 positioned directly below the discharge port 5a serves as a guide, and the parison P changes its direction by the roller 726, reaches the rear end of the conveyor 72 together with the belt 724, and is discharged from the machine.
[0047]
The discharge amount (discharge speed) of the parison P is detected by a sensor or the like (not shown). Then, when the discharge amount (discharge speed) of the parison reaches a preset value (step S15), the mold 220 of the rotary molding machine starts to rotate (step S16).
At the same time, the temperature rise of the cutter 736 is started (step S17).
After the temperature of the cutter 736 is sufficiently raised, as shown in FIG. 10A, the cylinder 732 is driven to cut the parison P with the cutter 736 (step S18). The cutting of the parison P by the cutter 736 is performed intermittently until a first blow button (not shown) for starting the supply of the parison P to the mold 220 is operated (steps S19 and S20).
[0048]
When the first blow button is operated (step S19), the parison P is cut by the cutter 736 at a preset timing, and the parison discharged from the discharge port 5a as shown in FIG. 10B. The parison cutting unit 73 and the conveyor 72 are moved back to a position where they do not interfere with P (step S21). Then, the parison is supplied from the die head 5 to the mold (step S22). The timing is set in advance so that the tip of the parison P is accurately supplied to a predetermined position of the mold 220 of the station (1), so that a complete molded product can be obtained from the first shot. it can.
[0049]
According to the rotary molding machine of this embodiment, a complete molded product can be molded from the first shot, and an incomplete molded product or an adjusted product is not molded. It is not necessary to remove the molded product or the adjusted product. Therefore, there is an advantage that the mold closing period can be lengthened.
FIG. 11 is a timing chart showing the opening / closing timing of the mold 220.
As shown in the figure, the mold opening may be started at the end of the station (6), and the mold opening timing in the conventional blow molding machine shown in FIG. 13 (shown by a two-dot chain line in FIG. 11) is rotated. The mold closing period can be lengthened by the angle α.
[0050]
This indicates that the rotation speed of the mold 220 can be increased by the rotation angle α. In this embodiment, the angle of the mold closing period which was initially 205 ° could be extended to 225 ° (α = 20 °), and the rotation speed of the mold 220 could be increased by about 10%. .
Thus, in the blow molding machine of this embodiment, the rotational speed of the mold 220 can be increased to increase the productivity of the molded product.
[0051]
Next, a procedure for preventing an incompletely molded product from being molded when the rotation of the mold 220 is stopped will be described.
As shown in FIG. 12A, when the mold 220 is rotated and the molded product is being molded, the conveyor 72 and the parison cutting portion 73 of the timing adjusting device 7 are in the retracted position, and the die head 5 The parison discharged from is supplied to the mold 220.
When, for example, an operator operates an operation button (die rotation stop means, not shown) for stopping the rotation of the mold 220 due to the production stop or the like, as shown in FIG. At the same timing, the conveyor 72 of the timing adjusting device 7 advances, and the parison discharged from the die head 5 is received by the belt 724.
[0052]
The advance timing of the conveyor 72, that is, the timing of stopping the parison supply to the mold 220 is set in advance so that a complete molded product is formed by the final shot including the end of the parison. As described in the first embodiment, for example, the timing is such that the motor drive pulse of the rotation drive unit 65 (see FIG. 13) that rotates the mold 220 is counted, and the mold 220 next to the last shot is counted. When entering the station (1), adjustment is made so that the parison is not supplied to the mold 220.
Even after the operation button is operated, the mold 220 continues to rotate for a while, and all molded products in the mold 220 are taken out by the molded product take-out section 8 (see FIG. 13) at the station (7). After that, it stops automatically.
[0053]
As described above, the conveyor 72 is advanced so that the parison discharged from the die head 5 is received by the belt 724, and the cutter 736 is intermittently advanced / retracted to be discharged from the discharge port 5a. The parison may be cut.
[0054]
Although preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments.
For example, in the above description, the valve body 232 and the contact member 234 are moved forward and backward by the cylinder 231, but the driving body is not limited to the cylinder 231, and other driving bodies such as a motor and a solenoid may be used. Good.
[0055]
Further, the low temperature air is supplied to the mold 220 from the outer peripheral side of the rotary shaft 651 without passing through the rotary shaft 651, but the low temperature air is supplied to the mold 220 through the inside of the rotary shaft 651. Also good. In this case, a resin or ceramic coating excellent in heat insulation may be formed on the inner peripheral surface of the low-temperature air circulation hole.
[0056]
Furthermore, as an example of extending the mold closing period, the timing of supplying the material to the mold 220 and adjusting the timing of stopping the material supply have been described as examples, but the mold closing is performed by other means. As long as the period can be extended, the means is not necessarily limited to the means described in the above embodiment.
[0057]
【The invention's effect】
As described above in detail, according to the present invention, the timing of opening formation can be easily adjusted, and the timing can be changed and adjusted even during the operation of the molding machine. Quality can be improved. Moreover, exhaust can be performed quickly to increase the rotational speed of the mold, and productivity can be improved. In particular, when used in combination with air blowing with cooling air or extending the mold opening / closing period, the productivity of the molded product can be improved by about 15% to 25%.
[Brief description of the drawings]
[Figure 1] First reference example of exhaust device and exhaust method (A) shows the state before the start of exhaust, and (b) shows the state at the start of exhaust.
FIG. 2 is a chart showing timing for opening and closing exhaust holes.
[Fig. 3] Second reference example of exhaust device and exhaust method FIG.
FIG. 4 shows an exhaust apparatus and exhaust method according to the present invention. Embodiment FIG.
FIG. 5 is a front view of an essential part of an embodiment of a rotary molding machine used for carrying out the present invention.
FIG. 6 is a graph showing changes in temperature at the bottom of a bottle when low temperature air having a temperature of −35 ° C. is used as blow air.
FIG. 7 is a front view of an essential part of an example of a rotary molding machine capable of extending the mold closing period of the mold.
FIG. 8 is a flowchart for explaining a material supply procedure by the timing adjustment device of FIG. 7;
FIG. 9 is a schematic diagram for explaining the operation of the timing adjustment device of FIG. 7;
FIG. 10 is a schematic diagram for explaining the operation of the timing adjustment device continued from FIG. 9;
FIG. 11 is a timing chart illustrating a mold closing period of a mold when a timing adjusting device is used.
FIG. 12 is an operation diagram for explaining the procedure for stopping the supply of material by the timing adjustment device.
FIG. 13 It is a front view of the principal part concerning the prior art example of the rotary blow molding machine for hollow container molding .
FIG. 14 is a diagram illustrating a configuration of exhaust holes formed in a mold.
[Explanation of symbols]
223 Exhaust hole
231 and 233 cylinder (drive means)
232 Disc
233 Contact member
235 Pressure chamber
236 Switching valve

Claims (7)

A material is supplied from the material supply unit to the mold, and air is blown into the material in a closed state to form a molded product of a predetermined shape, and then an opening is formed in a part of the molded product to form the molded product. An exhaust device for blow air in a blow molding machine that exhausts air inside
An exhaust hole formed in the mold;
Opening and closing means for opening and closing the exhaust hole;
Control means for controlling the timing of opening the exhaust hole by the opening and closing means;
I have a,
Blowing said closing means holds the interior of the exhaust hole at a predetermined pressure, when exhausting the internal air of the molded article, characterized by switching valves der Rukoto for opening the exhaust hole Blow air exhaust system for molding machines. The blow molding machine is a rotary molding machine in which a plurality of molds are annularly arranged on a base, and a molded product having a predetermined shape is molded while rotating the mold together with the base. An exhaust device for blow air in the blow molding machine according to claim 1 . A blow air exhaust method in a blow molding machine that supplies a material from a material supply unit to a mold and blows air to the material at a predetermined position to form a molded product of a predetermined shape,
An exhaust hole having a predetermined diameter is previously formed in the mold,
When opening and closing the exhaust hole at a predetermined timing and opening the molded product by the pressure of blow air ,
The blow product is characterized by holding the pressure in the exhaust hole at a predetermined pressure and releasing the air in the exhaust hole to the atmosphere at the predetermined timing, thereby opening the molded product by the pressure of the blow air. A method of exhausting blow air in a molding machine. The method for exhausting blow air in a blow molding machine according to claim 3 , wherein low-temperature air in a range of -30 ° C to -40 ° C is used as blow air. The period closed mold the mold is closed, blow air method of the exhaust in the blow molding machine according to any one of claims 3 or 4, wherein the mold has a during rotation 225 °. The blow molding machine is a rotary type molding machine, and the supply of the material pre-sets the material supply start timing from the material supply unit based on the peripheral speed of the mold; and the material when the discharge of the material is started from the supply unit, and a step for advancing the material pulling means to the material supply section side, it receives the material discharged from the material supply portion in the material pulling means, circumference of the mold The step of pulling the material in one direction at the same speed as the speed or faster than the peripheral speed, and after the discharge amount or discharge speed of the material reaches a preset amount or speed, the material cutting means and cutting the material, along with cutting the material, the material tensile retracts at a preset timing means, and a step of initiating the supply of material into the mold from the material supply unit, wherein Blow air method of the exhaust in the blow molding machine according to any one of claims 3-5, characterized in that to adjust the timing for supplying the material to the mold. The blow molding machine is a rotary molding machine, and the step of presetting the supply of the material based on the peripheral speed of the mold and the mold rotation stopping means are operated. A step of advancing the material pulling means toward the material supply unit at the stop timing, and rotating a predetermined number of molds after the mold rotation stopping means is operated, The method for exhausting blow air in a blow molding machine according to any one of claims 3 to 6 , wherein a timing for stopping the supply of the material to the mold is adjusted.

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