Planetary extruder for thermoplastics material

• US 4,268,176 A
• Filed: 01/09/1980
• Issued: 05/19/1981
• Est. Priority Date: 01/12/1979
• Status: Expired due to Term

• Current Assignee: Hermann Berstorff Maschinenbau GmbH (KraussMaffei Group GmbH)
• Original Assignee: Hermann Berstorff Maschinenbau GmbH (KraussMaffei Group GmbH)
• Inventors: Muller, Werner
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US06/110,684
• Time in Patent Office: 496 Days
• Field of Search: 366/83-86, 366/300, 366/301, 425/204, 425/208, 264/349
• US Class Current: 366/83
• CPC Class Codes: B29B 7/426 with consecutive casings or screws, e.g. for charging, discharging, mixing
• CPC Class Codes: B29B 7/485 with three or more shafts provided with screws
• CPC Class Codes: B29B 7/487 with consecutive casings or screws, e.g. for feeding, discharging, mixing
• CPC Class Codes: B29B 7/488 Parts, e.g. casings, sealings; Accessories, e.g. flow controlling or throttling devices discharging B29B7/582; feeding B29B7/60
• CPC Class Codes: B29C 48/03 characterised by the shape of the extruded material at extrusion
• CPC Class Codes: B29C 48/435 Sub-screws
• CPC Class Codes: B29C 48/44 Planetary screws

Abstract

In a planetary extruder for extruding thermoplastics materials, a threaded main spindle is meshed with and surrounded by threaded planetary spindle. To improve pull-in of material, the planetary spindles are provided in groups, each group comprising at least three spindles. The first planetary spindle of each group corresponds in length to the main spindle and succeeding spindles, considered in an opposite direction to the direction or orbital movement of the planetary spindles, of each group are each shorter than the spindle which immediately precedes it to form receiving spaces for material fed by a feed screw, which receiving spaces in operation are continuously enlarging.

In one embodiment in each group, the spindles which are successively shorter are followed by spindles which are successively longer.

Claims

1. In a planetary roller extruder for thermoplastic material, which said extruder has a main screw threaded spindle, a plurality of screw threaded planetary spindles meshed with said main spindle and a feed screw, at an intake end of said extruder, with said main spindle secured against relative rotation with respect to said feed screw, the improvement comprising providing said planetary spindles in groups with each of said groups comprising at least three of said planetary spindles and with said planetary spindles of each of said groups successively shorter, considered in a direction around said main spindle opposite to the direction in which said planetary spindles orbit around said main spindle in operation, to form receiving chambers for said material fed by said feed screw and to be extruded.

2. The invention claimed in claim 1, wherein, in each of said groups, said ones of said planetary spindles which are successively shorter are followed by at least one of said planetary spindles of that group which is longer than that one of said planetary spindles of that group which immediately precedes it.