| 摘要 |
1,230,328. Extruding tubes. R. HAGEN, [trading as KAUTEX - WERK REINOLD HAGEN]. 11 March, 1969 [18 March, 1968], No. 12872/69. Heading B5A. In a tube-forming die head, particularly intended for use in conjunction with blowmoulding machines, material flows to the die orifice via an annular passageway and is temporarily stored within the head by acting on an annular piston therein to retract the piston, a lateral surface thereof defining part of the annular passageway when the piston is not retracted. In the embodiment shown, piston 216 retracts into chamber 226 formed in a mandrel 215 supported within housing 214 by fins 233, the outer lateral surface of the piston defining part of passageway 223. In its retracted position, as at 216a, the piston actuates a limit switch 241 via a spring 242 at a predetermined pressure, thereby allowing access to chamber 226 via conduit 240 for hydraulic fluid which forces the piston to extrude the accumulated material. With this arrangement, material which is first stored is also first extruded. In a further three embodiments, Figs. 1, 2 and 4 (not shown), the piston retracts within a chamber formed in the easing of the die head, the inner lateral surface of the piston in each case defining part of the annular passageway. The main differences between these embodiments is in the configuration and mounting of the mandrel and the position of the piston relative thereto. |
