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EP-4302969-B1 - HOLLOW CONTAINER MANUFACTURING APPARATUS

EP4302969B1EP 4302969 B1EP4302969 B1EP 4302969B1EP-4302969-B1

Inventors

  • YOSHIOKA JUNYA
  • USUKI Noriyoshi
  • FUKUDA KEIKO
  • NAKAYAMA KIYOTAKA
  • NAITO AKIHIRO
  • UEMURA TAKASHI
  • SUSA KEIGO
  • MATSUZAKI KOJI
  • NISHIDA SHOSO

Dates

Publication Date
20260506
Application Date
20220228

Claims (11)

  1. A hollow container manufacturing apparatus (100) comprising: a fixed molding die (1) having a cavity (11); a movable molding die (2) having a cavity (21) and moved in a direction of coming closer to or away from the fixed molding die; a heating unit (3) to be placed between the fixed molding die and movable molding die to heat a pair of workpieces (w1 , w2) in the cavities (11, 21) of the fixed molding die and movable molding die; guide rails (13) to move the heating unit; and a drive mechanism (4) to move the heating unit back and forth with respect to the fixed molding die (1) or the movable molding die (2), along the guide rails (13), wherein the pair of workpieces (w1 , w2) is heated by the heating unit (3) and then welded to each other, and the apparatus (100) is characterized in that the guide rails (13) to move the heating unit are partly arranged either in an opposing surface of the fixed molding die (1) to oppose the movable molding die (2) or in an opposing surface of the movable molding die to oppose the fixed molding die.
  2. The hollow container manufacturing apparatus according to claim 1, wherein each of the pair of workpieces (w1 , w2) includes at least a bottom and a peripheral wall rising from the bottom, and the apparatus (100) further includes holding mechanisms (16; 17) to partly press the pair of workpieces, in the respective cavities (11, 21) of the fixed molding die (1) and movable molding die (2), against the fixed molding die and movable molding die, respectively.
  3. The hollow container manufacturing apparatus according to claim 2, wherein the holding mechanisms (16) each have a cylinder (162) and a partial core (161) moved back and forth by the cylinder, wherein the partial cores are moved forward by the cylinders to partly press the workpieces (w1, w2) against the fixed molding die (1) and movable molding die (2), respectively.
  4. The hollow container manufacturing apparatus according to claim 2, wherein the holding mechanisms (17) each include a force-exerting means (172) to exert a force from outside to a side surface of each of the workpieces (w1, w2), and a pressing part (171) provided at a front end of the force-exerting means, wherein the workpieces are partly pressed against the fixed molding die (1) and movable molding die (2), respectively, by respective forces by the force-exerting means.
  5. The hollow container manufacturing apparatus according to any one of claims 1 to 4, further comprising: a centering mechanism (60; 70; 80) to make a distance between the heating unit (3) and the fixed molding die (1) equal to a distance between the heating unit and the movable molding die (2), after the heating unit has been placed between the fixed molding die and movable molding die.
  6. The hollow container manufacturing apparatus according to claim 5, wherein the centering mechanism (60) includes: a middle plate (61) projecting outside the heating unit (3); a first spring (62) interposed between the middle plate and the fixed molding die (1); and a second spring (63) interposed between the middle plate and the movable molding die (2) and having the same spring constant as the first spring.
  7. The hollow container manufacturing apparatus according to claim 5, wherein the centering mechanism (70) includes: a guide plate (72) projecting outside the heating unit (3); a centering guide rail (71) to which the guide plate is fitted; a pair of racks (74) attached to the fixed molding die (1) and movable molding die (2) and extending in a direction of the movable molding die being moved; a gear (75) meshing with the pair of racks; and a gear box (76) housing the gear and portions of the pair of racks and attached to the centering guide rail (71).
  8. The hollow container manufacturing apparatus according to claim 5, wherein the centering mechanism (80) includes: a guide plate (72) projecting outside the heating unit (3); a centering guide rail (71) to which the guide plate is fitted; a first link (81) whose center is rotatably fixed to the centering guide rail; and a pair of second links (82) each having a first end rotatably fixed to each of ends of the first link and a second end rotatably attached to each of the fixed molding die (1) and movable molding die (2).
  9. The hollow container manufacturing apparatus according to any one of claims 1 to 8, wherein in a case where the heating unit (3) is brought into contact with the pair of workpieces (w1, w2) during welding, the fixed molding die (1) or movable molding die (2) includes a first communication hole (18) to communicate with outside, and the heating unit includes a second communication hole (32) to communicate with the first communication hole.
  10. The hollow container manufacturing apparatus according to any one of claims 1 to 8, wherein in a case where the heating unit (3) is brought into contact with the pair of workpieces (w1, w2) during welding, the heating unit includes a heater communication hole (33) to let out air in the fixed molding die (1) and movable molding die (2).
  11. The hollow container manufacturing apparatus according to any one of claims 1 to 8, wherein in a case where the heating unit (3) is not brought into contact with the pair of workpieces (w1, w2) during welding, the heating unit has a protective frame (31) surrounding the heating unit, wherein the protective frame is moved back and forth with respect to the fixed molding die (1), together with the heating unit and along the guide rails (13) used for moving the heating unit.

Description

TECHNICAL FIELD The present invention relates to a hollow container manufacturing apparatus. BACKGROUND ART There has been an apparatus of manufacturing a hollow container with a hollow interior, such as a fuel tank for storing fuel (see Patent Document 1). A conventional hollow container manufacturing apparatus forms a pair of half hollow molds (workpieces) by primary molding, then heats ends of peripheral walls of the molds with a heating unit such as a heater, and welds the ends such as by vibration welding. The conventional hollow container manufacturing apparatus is provided with a heating device to hold one end of the heating unit and move the heating unit back and forth, with respect to molding dies. In addition, Patent Document 2 discloses a molding method for a hollow molded product, a hollow molded product and an apparatus for manufacturing the same. The method includes: a primary molding in which a movable and fixed dies are used to mold a pair of semi-molded products, the movable mold is moved relative to the fixed mold, with one of the pair remaining in the fixed mold and the other of the pair remaining in the movable mold, to cause joining end surfaces of the pair to face each other at a distance, and a heater is inserted between, and melt, said surfaces; and a secondary molding in which the dies are closed and the joining end surfaces are crimped to obtain a hollow molded product. Patent Document 3 discloses a heating element welding machine, and method for quick refitting of tools of heating element welding machines. PRIOR ART DOCUMENT Patent Document Patent Document 1: Japanese Patent No. 6657280;Patent Document 2: Japanese Patent No. 5073704 B2; andPatent Document 3: European Patent Application Publication No. 1572437 B1 SUMMARY OF THE INVENTION Problems to be Solved A conventional hollow container manufacturing apparatus including a heating unit for welding workpieces has the heating unit with a cantilever structure. Accordingly, the heating unit has, with respect to one end thereof supporting the heating unit, a risk of the other end thereof (front end in a direction of the heating unit being moved forward) being tilted downward or vibrated. The Applicant has found that if the heating unit were tilted or vibrated, positioning the heating unit becomes difficult, so that temperature varies at ends of the workpieces, to have a risk of poor welding. In addition, for manufacturing a large hollow container, size of the heating unit is also increased accordingly, to make the above-described problem more evident. The present invention has been devised from such a point of view, and is intended to provide a hollow container manufacturing apparatus to facilitate positioning a heating unit with respect to a pair of workpieces and increase welding strength. Solution to Problems In order to solve the above-described problem, the present invention provides a hollow container manufacturing apparatus including: a fixed molding die having a cavity; a movable molding die having a cavity and moved in a direction of coming closer to or away from the fixed molding die; a heating unit to be placed between the fixed molding die and movable molding die to heat a pair of workpieces in the cavities of the fixed molding die and movable molding die; guide rails to move the heating unit; and a drive mechanism to move the heating unit back and forth with respect to the fixed molding die or the movable molding die, along the guide rails, wherein the pair of workpieces is heated by the heating unit and then welded to each other. The guide rails to move the heating unit are partly arranged either in an opposing surface of the fixed molding die to oppose the movable molding die or in an opposing surface of the movable molding die to oppose the fixed molding die. A conventional hollow container manufacturing apparatus has operated a heater device, having a heating unit, separately from molding dies. In contrast, according to the present invention, the guide rails, used for moving the heating unit, are partly arranged in the fixed molding die or the movable molding die, so that a distance between the heating unit and the fixed molding die or movable molding die remains unchanged even when the heating unit is moved back and forth. Additionally, the heating unit is free from vibration because the heating unit is moved back and forth on the guide rails. This facilitates positioning the heating unit with respect to the pair of workpieces, and evenly heating ends of the pair of workpieces. As a result, uneven heating can be eliminated or reduced, to increase welding strength. In addition, each of the pair of workpieces includes at least a bottom and a peripheral wall rising from the bottom, and the apparatus preferably further includes holding mechanisms to partly press the pair of workpieces, in the respective cavities of the fixed molding die and movable molding die, against the fixed molding die and movable molding die, resp