JPS5947648B2 - Continuous molding machine for plastic hollow bodies - Google Patents

Description

[Detailed Description of the Invention] In this invention, a continuously extruded plastic tube (hereinafter referred to as a parison) is held between a pair of split molds, and a pressurized fluid is blown into the parison to form it into a desired shape. This invention relates to a continuous molding machine for plastic hollow bodies.

Conventionally, parisons are continuously fed vertically downward, and the parisons are successively clamped by a plurality of split molds that rotate in a vertical plane at predetermined intervals, and the parisons are molded in the molds to form plastic. 1. A molding machine that can continuously manufacture hollow bodies is used.

However, this type of molding machine has the disadvantage that the unmolded parison between the molds is wasted, resulting in a poor product yield. Therefore, recently, the molds are moved in a straight line near the position where the parison is held, and the molds are moved close to each other to minimize the amount of wasted parison remaining between the molds, for example, in Japanese Patent Publication No. 45-30231. Those described in official gazettes, etc. are considered. However, these devices have the disadvantage that they require a relatively large number of molds due to the nature of their mechanism, and also require major modifications to the equipment if the size of the mold, especially the length, changes. However, there was a problem in that it was not suitable for high-variety, low-volume production. This invention was made with attention to these circumstances.5
By adopting a new mechanism for moving and opening/closing the split molds, it goes without saying that it is possible to minimize the amount of paryrin wasted between molds, and also achieves high productivity with a small number of molds. To provide a continuous molding machine for plastic hollow bodies, which can easily handle changes in the dimensions of a mold by simply replacing the cam.

An embodiment of the present invention will be described below with reference to the drawings.

A drive shaft 1 is rotatably disposed with its axis oriented horizontally, and is rotated by a drive mechanism 2 at a predetermined speed.

In other words, there are support stands 9 erected at both ends of the base 3,
The proximal ends of hollow cylindrical adapters 7 and 8 are fixed to the upper ends of the adapters 10, respectively. Each of the adapters 7 and 8 has a flange portion at its tip; the end surfaces of the flanges are opposed to each other with a predetermined distance therebetween. Further, the adapters 7 and 8 are arranged horizontally with the axes of their respective hollow portions aligned, and the drive shaft 1 is inserted through both hollow portions.
This drive shaft 1 is connected to each of the above-mentioned adapters 7 through bearings.
8 and is rotatably supported. Both ends of the drive shaft 1 protrude outside the adapters 7 and 8, and a chain wheel 4 is fixed to one end of the protrusion, and a motor disposed on the upper surface of the base 3 is connected to the chain wheel 4. 6 and a reduction gear 5, the power of the drive mechanism 2 is transmitted through the chain 4a. On the other hand, a fixed cam ring 12 is disposed so as to surround the outer periphery of the rotating shaft 1, and annular fixed rails 13 and 14 are disposed further on the outer periphery of the fixed cam ring 12. That is, the fixed cam ring 12 is a plate-shaped member having a cam surface on the inner diameter side, and its end surface is detachably attached to the flange end surface of the adapter 8 with bolts.
Further, the fixed rails 13 and 14 are formed in the shape of a brim on the outer periphery of the end surface of disk-shaped rail plates 15 and 16 whose shaft centers are hollow. The end face of the rail plate 15 is fixed to the tip end face of the seven flange of the adapter 7, and the end face of the rail plate 16 is fixed to the rear end face of the flange of the adapter 8, respectively. These fixed rails 13 and 14 have the same shape and have a double structure of an outer rail formed along the outer peripheral edge of the rail plates 15 and 16 and an inner rail formed on the inner side thereof. The locus has a vertical straight portion 17 in one part and is a perfect circle in the other part. In addition, this fixed rail 13,
A plurality of carts 18 are installed at 14 so as to be freely movable along the rails. This trolley 18 has a mold mounting surface on the outer diameter side, and the fixed rails 13, 14 on the inner diameter side.
A cross section with wheel support legs drilled in the corresponding parts;
The fixed rails 13, 1 are fitted with the two pairs of rear wheels 20 attached to the rear portions of the wheel support legs and fitted between the grooves of each of the outer and inner rails.
The outer rails of each of No. 4 are sandwiched between them.

Further, each of the carts 18 and the drive shaft 1 are connected by arms 21, respectively. That is, the portion of the drive shaft 1 located between the tip surfaces of the flanges of the adapters 7 and 8 is shaped like a polygonal column, while the base end of the arm 21 has a leg portion with a width corresponding to one side of the polygonal column. Each arm has 2
The arms 21 are arranged radially around the drive shaft 1 by bringing the base end legs of the arms 21 into contact with each side surface of the polygonal column of the drive shaft 1. Further, the front end of the leg of each arm 21 and the front end of each side surface of the polygonal column portion of the drive shaft 1 are connected by a hinge 22, so that each arm 21 can be tilted. Further, an arm tip member is slidably inserted into the axial hollow portion of the arm 21 so that the arm 21 can expand and contract in a substantially radial direction of the drive shaft 1. Further, the tip of each arm 21 is rotatably pivoted to the inner diameter side bottom of each of the above-mentioned carts. Further, a cam roller 23 is rotatably attached to the adapter 8 side at the rear of the leg end of the arm 21. The outer peripheral surface of this cam roller 23 is brought into contact with the inner cam surface of the fixed cam ring 12 due to the gravity of the truck 18 or the arm 21, etc., and the forward inclination angle of each arm corresponds to the shape of the cam surface. We are trying to regulate what we have done. On the other hand, an extrusion die 24 is disposed above the outside of the vertical straight portions of the fixed rails 13, 14, so that the parison 25 is continuously fed downward parallel to the vertical straight portions of the fixed rails 13, 14. . Further, a split mold 26 is removably attached to each of the carts 18, and the split mold 26
The mold opening/closing mechanism 27 attached to the carriage 18 opens, closes and locks the mold in the outer diameter direction. That is, the fixed mold 28 of the split mold 26 is removably attached to the outer mold mounting surface of each truck 18. Further, a bracket 30 is attached to the side of the truck 18 by a dovetail groove so as to be slidable in the radial direction, and a mold opening/closing mechanism 27 is attached to this bracket 30. The mold opening/closing mechanism 27 is a split mold 2 of the bracket 30.
The base end of a mold holding arm 31 is rotatably attached to the upper end of the 6 side, and the movable mold 29 of the split mold 26 is held at the tip thereof, and this holding arm 31 is attached to the base end. The split mold 26 is preliminarily opened and closed by rotating around the part. Yasu ． The rotation of the holding arm 31 is achieved by transmitting the power of an opening/closing cylinder 32, which is attached to the lower part of the bracket with a piston rod oriented in the radial direction, to a pinion 33 fixed to the base end shaft of the holding arm 31, through a rack 43. It is done. Also, there is a rod 3 on the bottom plate on the inside diameter side of the bracket.
The proximal end of the rod 4 is fixed, and a roller 35 is rotatably attached to the tip of a rod 34 extending in the inner diameter direction. Further, this roller 35 is fitted into a cam groove of a mold opening/closing cam 36 fixed to the rear end surface of the flange of the adapter T, and the split mold 2
6 main opening/closing operations are performed. Further, the center portion of the mold holding arm and the outer diameter side tip portion of the bracket 30 are rotatably connected by a two-bar link 3T, and a locking cylinder 38 is attached to the center bendable portion of the link 31.
The tips of the piston rods are rotatably connected, and the main body of the cylinder 38 is rotatably attached to the bracket 30, so that when the split mold 26 is opened, the center of the link 3T can be bent. By pressing the portion 41 in the outer radial direction with the cylinder 38, the mold is locked. Also, there is a notch 39 in the center of the rod 3T.
A locking cam 39 fixed to the outer circumference of the adapter T causes a locking pawl 40 that moves in and out toward the rod 37 to fit into the notch 39 when the mold is closed, thereby locking the bracket 30, that is, locking the mold. I try to do this. Further, this mold opening/closing mechanism 2T closes and locks the split mold 26 when the split mold 26 reaches the vertical straight portion IT of the fixed rails 13, 14, and moves the parison 25 into the split mold. After the parison 25 is blow-molded into a hollow product within this split mold 26, this split mold 26 is opened. The vertical straight portions 11 of the fixed rails 13, 14 and related portions will now be described in more detail with reference to FIGS. T through 10. Figure T shows split mold 2
6 and the vertical straight portion 17, the split mold 26M indicated by a solid line in the figure is the largest dimension mold that can be used in this device, and the split mold 26M indicated by an imaginary line Type 2
6m is the minimum size mold. And al indicates the position where the largest split mold 26M clamps the parison 25, A2 indicates the position where the largest split mold 26m clamps the parison 25, and b indicates the vertical position of each of the split molds 26M) 26m. It shows the position immediately before leaving the straight section IT and returning to the circular orbit section. In other words, the vertical straight portion 17 is the largest split mold 26M.
It has dimensions that allow two units to be connected in series. In addition, the upper end 42 of this vertical straight portion IT, that is, the inner rail at the boundary between the circular track portion of the rails 13 and 14 and the vertical straight portion IT is
As shown in the figure, the front wheel 19 of the truck 18 that is fed into the upper end portion 42 is rotated inwardly than the rear wheel 20 that grips the outer rail, thereby causing the truck 18 to move rapidly in this portion. This prevents the parison 25 from interfering with the tip 26a of the split mold 26 on the carriage 18. Of course, one of the rear wheels 20 is slidably attached to the rear wheel 20 to prevent strain caused by the tilting movement of the truck 18. When installing a split mold 26 of general dimensions, that is, a mold having dimensions of the maximum DL mold 26m or more and less than the maximum split mold 26M, as shown in FIG. Ring 12
A relief portion 44 is provided on a part of the inner cam surface of the split mold 26 to allow the split mold 26 to run at a predetermined timing and speed, which will be described later. Here, the operation of this device will be explained.

First, if the drive mechanism 2 is operated to rotate the drive shaft 1 at a predetermined speed, each split mold on the fixed rails 13 and 14 ゜26
are respectively driven or regulated by the corresponding arms 21 and travel on the rails 13, 14 in a direction in which they are fed into the vertical straight portion IT from the upper end thereof. In this case, each split mold 26 runs at a constant speed in the circular orbit section with a predetermined distance from the preceding split mold, but performs a special operation in the vertical straight section 17. That is, as shown in FIG. 9, when the split mold 26 reaches the upper end 42 of the vertical straight portion IT, that is, when it reaches the position c in the figure, the cam roller 23 of the arm 21 corresponding to the split mold 26 reaches the relief portion 44 of the fixed cam ring 12. Therefore, from then on, as the drive shaft 1 rotates, the restriction on tilting of the arm 21 is released, and the splitting mold 2
6 performs a tilting operation by its own weight and is rapidly connected to the preceding split mold. In other words, the split mold 26 is rapidly fed from position c to position a. Then, at this position a, the mold opening/closing mechanism 2
7 operates to close the split mold 26, sealing the parison 25 in the mold 26 and molding the parison 25 into a hollow product by blow molding while continuing to run.
The mold is opened when the product has cooled and hardened. The split mold 26 travels at a constant speed from position a to position b to prevent the parison 25 above the mold from elongating or loosening, and the subsequent split mold 26 clamps the parison 25 above at position a. As soon as it does, it shifts from position b to the circular orbit section. This speed control is set by the cam curve of the latter half of the relief portion 44 of the fixed cam ring 12. As described above, hollow plastic bodies can be continuously molded, but since the parisons that are continuously extruded are received one after another by the mold without any gaps, there is no wasted parison remaining between the molds. Of course, the amount of mold can be minimized, and moreover, as a means of closely arranging the molds when enclosing the parison, the molds are connected to the preceding mold by rapid feeding. There is no need to arrange a large number of molds in a relatively dense manner in advance as in the conventional method, and therefore, the number of relatively expensive molds can be greatly reduced, making production, especially high-mix, low-volume production, more economical. It is something that can be done.

Furthermore, since the traveling speed of each split mold 26 is controlled by a single fixed cam ring 12, the configuration is simple and maintenance and inspection are easy. Even in the case of replacing the fixed cam ring 12 with one of a different shape, it is sufficient to simply replace the fixed cam ring 12 with one of a different shape, and therefore, it is possible to quickly and easily change the setup of the molded product. Note that the means for attaching the fixed cam ring is not limited to the one having the above-mentioned configuration, but may be any other means, and in short, any known means may be used as long as it is an attaching means that can be easily replaced.

As detailed above, by adopting a new mechanism for moving and opening/closing the split molds, it goes without saying that the parisons wasted between molds can be minimized, and moreover, it is possible to efficiently use a small number of molds. It is possible to provide a continuous molding machine for plastic hollow bodies that can be operated and can be adapted to changes in the dimensions of a mold by simply replacing the fixed cam ring.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of the present invention, FIG. 2 is a side sectional view of the same embodiment, FIG. 3 is a side view showing a mold opening/closing mechanism, and FIG. 4 is a front view showing the same mechanism. Figure 5 is a sectional view taken along the line C-C in Figure 4, Figure 6 is a view taken along arrow A in Figure 4, and Figures 7 to 9 explain the operation of the split mold in the vertical straight section of the fixed rail. Figure 10 is an explanatory diagram for
It is a BB arrow directional view in a figure. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2... Drive mechanism, 12... Fixed cam ring, 13, 14... Fixed rail, 17... Vertical straight part, 18... Dolly, 21... Arm , 22...
Hinge, 23...Roller, 24...Extrusion die, 25
... Parison, 26... Split mold, 27... Mold opening/closing mechanism, 44... Relief part.

Claims (1)

[Claims] 1. An annular fixed rail having a vertical straight portion in part, an extrusion die disposed above the outside of the vertical straight portion of the fixed rail and continuously supplying the parison downward parallel to the vertical straight portion, and the fixed rail. A plurality of carts are moved along the rails, a split mold is provided for each of the carts, and the split mold is closed by the vertical straight section of the fixed rail to confine the parison in the split mold, and the parison is blown into the split mold. A mold opening/closing mechanism that opens the split mold after the parison is formed into a hollow product by molding, and a mold opening/closing mechanism that opens the split mold after the parison is formed into a hollow product, and a mold opening/closing mechanism that is arranged at the center of the annular fixed rail and that connects each of the carts to the vertical straight part of the rail at its upper end. A drive shaft that rotates in the feeding direction, and a plurality of legs whose legs are tiltably connected by hinges at equal intervals on the outer circumferential surface of the drive shaft, and whose upper ends are pivotally connected to each of the corresponding carts. a telescoping arm, a cam roller rotatably attached to the leg of each arm, and a cam roller coaxially disposed around the outer periphery of the drive shaft, supporting the cam roller with its inner cam surface to support the arm. a fixed cam ring that restricts the tilting of the drive shaft and transmits the driving force of the drive shaft to the trolley via the arm; and a fixed cam ring provided on a part of the cam surface of the fixed cam ring, the upper end of the vertical straight part of the annular rail. The mold is equipped with a relief part that releases the restriction on tilting of the arm connected to the cart that supports the split mold that reaches the part, and allows the split mold to tilt by its own weight and rapidly connect to the preceding split mold. A continuous molding machine for plastic hollow bodies.