JP2008254281A - Material bridge prevention structure in supply port of injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a material bridge in a supply port by operating an oscillating member through utilization of material movement in a supply port without depending on the relation with a screw flight. <P>SOLUTION: The oscillating member is provided by being hung by supporting the upper part with a holder to the place where a lower end is positioned in the vicinity of the inner peripheral edge of a heating cylinder in the supply port of the heating cylinder with a built-in injection screw. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a material bridging prevention structure for preventing a bridging phenomenon of a molding material which causes a material clogging in a supply port provided in an injection apparatus.

Conventionally, in a connecting path (supply port) between a hopper and a cylinder, a rod body is swingably supported by a mandrel and provided at a position where the lower end is located in a screw groove between the screw flights, By repeatedly tilting the rod due to interference with the lower end of the rod and returning by jumping over the flight edge at the lower end due to a change in the tilt angle, the stirring portion at the upper end is swung with the rod to prevent material bridges from occurring. is doing.
JP-A-57-113029

  In the above prior art, due to the displacement of the screw flight in the circumferential direction due to the rotation, the lower end of the rod in the screw groove is pressed forward against the screw front surface. This pressing is performed until the lower end of the rod body is tilted and the lower end is disengaged from the flight edge, so that the abutting portion is rubbed by the lower end and easily wears. It becomes wrinkles due to partial wear on the flight edge, and fine material waste tends to adhere. Most of this material scrap is scraped off by the rod, but some remains. Moreover, since the lower end of the rod body also wears, there is a problem that the life is short and the replacement frequency is increased.

  The extrusion screw in the heating cylinder of the extruder is only rotating in the heating cylinder and does not move back and forth, so even if a flaw due to a rod occurs on the front of the flight or part of the flight edge, that part is always supplied. It is located under the mouth, so that the material waste adhering to the coffin part is not melted by heat transfer from the heating cylinder, so some soot is acceptable, but the injection screw moves forward and backward in the heating cylinder In the apparatus, it becomes a cause of generation of defective molded products, so that the wrinkle of screw flight becomes a problem.

  This is because the injection screw repeats retreat (material weighing) and advance (injection). When wrinkles are generated in the screw flight and the material waste adheres to the flange portion, the material waste moves into the heating cylinder together with the screw flight by the screw advance and is heated. The heating melts the surface and makes it difficult for it to fall off the ridge, and new material scraps adhere to it. This may be repeated to increase the bulk, and some may fall off in the middle, while others may stay attached for a long time and carbonize before peeling off. The increase in the adhered material in the heel portion causes a problem of material transfer due to screw rotation, and carbonization causes a black spot of the molded product, which causes a defective molded product. For this reason, it is said that the screw flight must be free from wrinkles in the injection device.

  The present invention has been conceived in order to solve the above-described conventional problems. The object of the present invention is to provide a screw flight even when a swing member is vertically provided in a supply port as a means for preventing material bridges. To provide a material bridge prevention structure that can reliably prevent the occurrence of a material bridge without affecting the screw flight by operating the swing member by moving the material in the supply port regardless of the relationship is there.

  This invention according to the above object comprises a heating cylinder having a nozzle at the front end and a supply port on the rear part, and an injection screw inserted into the heating cylinder so as to be rotatable and movable back and forth, and molded from the supply port into the heating cylinder. In the injection apparatus for supplying and dropping the material, the swinging member is supported in the supply port by a holder, and the lower end is hung up to a position near the inner peripheral edge of the heating cylinder.

  The holder includes at least a seat plate having a hole with the same diameter as the supply port, and a support unit that is integrated with the seat plate and formed at the center of the hole by a plurality of arms. The upper part of the moving member is inserted and fixed, and the swinging member is suspended from the center of the supply port. The swinging member is a vertically long plate-like body having a mounting bar at the upper center. The plate surface of the plate is directed in the flow direction of the molding material in the supply port, and the upper portion of the rod is inserted and fixed to the support portion of the holder.

  In the above configuration, the rocking member swings in the flow direction in the lower part of the supply port due to the flow force of the molding material due to the repeated rotation and backward movement of the injection screw, so that the molding material in the lower part of the supply port is in the central part. Therefore, the material bridge is not generated in the lower end portion of the supply port, which is considered to be due to the overcrowding of the molding material due to the material pressure, and the supply failure due to the material clogging can be avoided. Further, since the lower end of the swing member is located in the vicinity of the inner peripheral edge of the heating cylinder that does not interfere with the screw flight, the screw flight is not affected by the swing member.

  In the figure, reference numeral 1 denotes a heating cylinder having a nozzle at the tip, and an injection screw 2 is provided in the inside thereof so as to be rotatable and movable back and forth. An installation cylinder 3 of the supply device is fitted in the rear part of the heating cylinder 1, and the rear end protruding from the installation cylinder 3 is held on the fixing unit 4 and is provided horizontally on the machine base. Further, a supply port 6 is formed in the installation base 5 integrally formed on the rear part of the heating cylinder 1 and the upper part of the installation cylinder 3, and the hopper 7 has the same inner diameter as the supply port 6 in the installation base 5. A holding base 8 formed integrally with a flange 8a is placed and fixed at the lower end of the cylindrical body.

Reference numeral 9 denotes a rocking member for preventing material bristling vertically provided at the center of the supply port 6. The upper peripheral edge 1 of the heating cylinder 1 is secured to the holder 10 and the lower end does not contact the screw flight 2 ′. ′ (See FIG. 4) is hung up to a position located in the vicinity. As shown in FIGS. 4 and 5, the rocking member 9 is composed of a plate-like body formed by attaching a short rod 9b to both sides of a long central rod 9a. The upper part of 9a is formed into a threaded rod to form a mounting rod. The diameter and length of each rod are set for the dimensions of the supply port. For example, the diameter of the supply port is 50 mm, the diameter of each rod is 6 mm, and the length of the central rod (screw shaft is 105 mm), the length of the rods on both sides is 67 mm, and the pressure receiving area of the plate-like body is 12,06 cm ² .

  The holder 10 includes a seat plate 12 having a hole portion 11 having the same diameter as the supply port 6 and a support portion 14 formed integrally with the seat plate 12 and formed at the center of the hole portion by a plurality of arms 13. The seat plate 12 is sandwiched between the installation base 5 and the holding base 8, and the rocking member 9 attached to the support portion 14 is supported at the center of the supply port 6.

  The rocking member 9 is a loose hole in which the plate surface is oriented in advance so that the plate surface is positioned in the flow direction of the molding material in the supply port, and the screw shaft at the upper part of the central rod is formed in the support portion 14. The upper and lower sides are fastened with nuts and are swingably suspended from the holder 10. Although not shown in the figure, in some cases, the swinging member may be provided with a stopper for positioning.

  In the injection device, the molding material such as granular or powdery or flakes (flakes) of the supply port 6 is transferred to the front of the heating cylinder through the rotating screw flight 2 ′ by rotating the screw (left rotation). Then, it is heated and melted in the transfer process and measured (accumulated) in the front part of the heating cylinder. Further, the injection screw 2 continues to move while retreating to the set position while rotating as shown in FIG. 2 due to the reaction force and the measured material pressure in the transferring process. At the supply port 6, the molding material dropped into the screw groove is pushed into the heating cylinder by the screw flight 2 ′, and subsequently, the molding material dropped into the screw groove is similarly pushed and transferred. Due to the inertia associated with the continuation of the transfer, the molding material in the lower end flows obliquely in the transfer direction (the front side of the supply port), and the momentum of the flow increases as the screw flight 2 'is approached.

  When the material flow occurs obliquely in the lower end of the supply port 6, the lower end portion of the swinging member 9 suspended in the supply port and buried in the material is pressed by the flow force and tilts upward in the flow direction. This inclination is maintained by the flowing molding material. Further, since all of the molding material in the screw groove is fed into the heating cylinder before the supply port 6 by the rotation of the screw, the screw groove after the supply port 6 is sent out even if the molding material flows in, so it is almost empty. It is in the state of.

  When the injection screw 2 moves back to the set position and stops the metering, when the injection screw 2 is moved forward from that position and the metering material is injected without rotating the screw, the metering material is moved backward from the supply port 6 as shown in FIG. The empty screw grooves that have been positioned sequentially pass under the supply port 6. With this passage, the molding material falls into the screw groove directly below. As a result, the tilted swinging member 9 is returned to its original posture by the fluid force caused by the dropping of the molding material.

  Accordingly, the rocking member 9 is swung in the flow direction by the flow force of the molding material in the lower part of the supply port 6 by repeated rotation and retreat and advance of the injection screw 2 performed every time the material is metered and injected. Since the molding material in the lower portion of the mouth 6 continues to be shaken at the central portion, a material bridge in the lower end portion of the supply port 6 that is caused by overcrowding of the molding material due to material pressure from above does not occur, Material clogging of the supply port 6 due to the material bridge is prevented. Further, even if the swing member 9 swings, the lower end does not come into contact with the screw flight 2 ′, so that the screw flight 2 ′ is not damaged by the suspension of the swing member 9.

  In the above embodiment, the rocking member 9 is formed as a plate-like body by a plurality of rods. However, the rocking member 9 can be suspended from the supply port by the holder, and the flow force of the molding material Therefore, the present invention is not limited to the illustrated embodiment.

It is a vertical side view except a part of injection device provided with the material bridge prevention structure concerning this invention in the supply port. It is a principal part vertical side view of the injection apparatus in the middle of screw retreat at the time of material measurement. It is a principal part vertical side view of the injection apparatus at the time of injection advance. It is a vertical front view of a supply port part. It is a perspective view of a rocking member and a holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating cylinder 1 'Inner peripheral edge of a heating cylinder 2 Injection screw 2' Screw flight 4 Fixing part of injection apparatus 5 Installation stand 6 Supply port 7 Hopper 8 Holding holder 9 Hopper member 9a Center rod 9b Rod on both sides 10 Holder 11 Hole 12 Seat Plate 13 Arm 14 Support Section

Claims (3)

An injection device comprising a heating cylinder having a nozzle at the front end and a supply port on the rear part, and an injection screw inserted into the heating cylinder so as to be rotatable and movable back and forth, and to drop the molding material from the supply port into the heating cylinder In
A structure for preventing material bridging in a supply port of an injection apparatus, wherein a swinging member is supported in the supply port by a holder so that the upper portion is supported and a lower end is provided in the vicinity of the inner peripheral edge of the heating cylinder.   The holder includes at least a seat plate having a hole portion having the same diameter as the supply port, and a support portion that is integrated with the seat plate and formed at the center of the hole portion by a plurality of arms. 2. The material bridge preventing structure at the supply port of the injection apparatus according to claim 1, wherein the upper part of the member is inserted and fixed and the swinging member is suspended from the center of the supply port.   The oscillating member is a vertically long plate-like body having a mounting rod at the upper center, and the plate surface of the plate-like body is directed in the flow direction of the molding material in the supply port, and the upper portion of the rod is The material bridge prevention structure at the supply port of the injection apparatus according to claim 1, wherein the material bridge is inserted into and fixed to a support portion of the holder.

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