| CPC B29C 48/10 (2019.02) [B29C 48/151 (2019.02); B29C 48/16 (2019.02); B29C 48/255 (2019.02); B29C 48/49 (2019.02)] | 6 Claims |
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1. A flexible tube production apparatus for extruding a flexible tube, comprising:
two extruders configured to extrude resins different from each other;
two valves provided corresponding to the two extruders, respectively;
a kneading mechanism configured to knead the resins supplied from the two extruders via the two valves;
a die having a through hole through which a blade wire is inserted, and an extrusion port through which the resins kneaded by the kneading mechanism are extruded onto a surface of the blade wire passing through the through hole; and
a control device configured to control the two valves, wherein
each of the valves is capable of switching between a state where the corresponding extruder and the kneading mechanism communicate with each other and a state where communication between the corresponding extruder and the kneading mechanism is cut off,
the control device controls the two valves to switch from a first state where one extruder and the kneading mechanism communicate with each other and communication between the other extruder and the kneading mechanism is cut off, to a second state where the other extruder and the kneading mechanism communicate with each other and communication between the one extruder and the kneading mechanism is cut off, when the flexible tube is extruded,
each of the valves includes
a valve body having a pillar shape and rotatable about a central axis thereof between a first rotation position and a second rotation position, and
a case in which the valve body is rotatably accommodated,
the case is provided with a first resin supply path which communicates with the corresponding extruder, a second resin supply path which communicates with the kneading mechanism, and a resin discharge path for discharging the resin to the outside of the case,
the valve body is provided with
a first flow path which causes the first resin supply path and the second resin supply path to communicate with each other when the valve body is at the first rotation position, and
a second flow path which causes the first resin supply path and the resin discharge path to communicate with each other when the valve body is at the second rotation position,
the control device controls rotation of the valve body of each of the valves such that in the first state, the valve body of one valve corresponding to the one extruder is located at the first rotation position and the valve body of the other valve corresponding to the other extruder is located at the second rotation position, and in the second state, the valve body of the one valve corresponding to the one extruder is located at the second rotation position and the valve body of the other valve corresponding to the other extruder is located at the first rotation position,
the valve body has an end surface orthogonal to the central axis, and a first opening which is an upstream end of the first flow path, a second opening which is a downstream end of the first flow path, and a third opening which is an upstream end of the second flow path are provided on the end surface so as to be eccentric from the central axis of the valve body,
the case has a flat surface portion which is in surface contact with the end surface of the valve body, and a fourth opening which is a downstream end of the first resin supply path and a fifth opening which is an upstream end of the second resin supply path are provided on the flat surface portion, and
when the valve body is at the first rotation position, the first opening overlaps the fourth opening, the second opening overlaps the fifth opening, and the third opening is closed by the flat surface portion, and
when the valve body is at the second rotation position, the third opening overlaps the fourth opening, the first opening and the second opening are closed by the flat surface portion, and the fifth opening is closed by the end surface.
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