US 11,697,240 B2
Blown film forming apparatus
Takahiro Shiota, Kanagawa (JP)
Assigned to SUMITOMO HEAVY INDUSTRIES MODERN, LTD., Kanagawa (JP)
Filed by SUMITOMO HEAVY INDUSTRIES MODERN, LTD., Kanagawa (JP)
Filed on Mar. 31, 2021, as Appl. No. 17/219,056.
Claims priority of application No. 2020-062983 (JP), filed on Mar. 31, 2020.
Prior Publication US 2021/0299931 A1, Sep. 30, 2021
Int. Cl. B29C 48/92 (2019.01); B29C 48/325 (2019.01); B29C 55/28 (2006.01); B29C 48/00 (2019.01)
CPC B29C 48/92 (2019.02) [B29C 48/0018 (2019.02); B29C 48/325 (2019.02); B29C 55/28 (2013.01); B29C 2948/92152 (2019.02); B29C 2948/92428 (2019.02); B29C 2948/92647 (2019.02); B29C 2948/92904 (2019.02)] 19 Claims
OG exemplary drawing
 
1. A blown film forming apparatus comprising:
a die including a substantially columnar inner peripheral member and a substantially cylindrical outer peripheral member that surrounds the inner peripheral member, and extruding a resin from a lip formed between the inner peripheral member and the outer peripheral member; and
a plurality of die lip drive mechanisms including a fluid pressure actuator as a drive source and adjusting a lip width by applying a radially outward tensile load to the outer peripheral member,
wherein the outer peripheral member includes a plurality of tensile load receiving portions to each of which a tensile load is applied by the respective die lip drive mechanism, and a stiffness reducing portion that is provided between the plurality of tensile load receiving portions.